A series of unsymmetrical S-(bromodifluoromethyl)diarylsulfonium salts 1 were readily synthesized by treatment of corresponding (bromodifluoromethyl)arylsulfoxides 2 and substituted benzenes 3 with triflic anhydride in moderate to good yields. The unsymmetrical sulfonium salts 1 with different aryl groups having electron-donating or electron-withdrawing substituents can be nicely constructed depending on the choice of 2 and 3. Bromodifluoromethylation of alkynes was evaluated by using the selected diarylsulfonium salts 1 to provide the desired bromodifluoromethylated alkynes in moderate to good yields.
Newelectrophilic fluoroalkylating agents based on the sulfoximine skeleton as a common platform are described. We demonstrate the importance of the activating group, attached to the nitrogen, and its specificity for the fluorinated group to be delivered. As an application, a variety of unknown dichlorofluoro, bromodifluoro, and trifluoromethyl alkynes have been prepared using these reagents.
S-(fluoroalkyl)diphenylsulfonium salts have been successfully synthesized from the reaction between fluoroalkylsulfinates and triflic anhydride in dichloromethane through a one-pot procedure. These S-(fluoroalkyl)diphenylsulfonium salts have been demonstrated to be effective reagents to fluoroalkylate C-nucleophilic substrates. Ionic substitution and radical or halogenophilic mechanism might be all involved in the reactions.
An integrated fully differential CMOS transimpedance amplifier (TIA) with buried double junction photodiode input is described. The TIA features a variable high transimpedance gain (250 kΩ to 2.5 MΩ), large DC photocurrent rejection capability (>55 dB) and low input referred noise density at 100 kHz (2pA/√Hz).
Mg(0)-promoted debromometalation of gem-difluoropropargyl bromides
作者:Masayuki Mae、Jiyoung A. Hong、Gerald B. Hammond、Kenji Uneyama
DOI:10.1016/j.tetlet.2005.01.130
日期:2005.3
Mg(0)/Me3SiCl was found to be effective for the preparation of difluoropropargylsilanes. This method, using Me3SnCl, produced the corresponding propargylstannane. (C) 2005 Elsevier Ltd. All rights reserved.